1. Field of the Invention
The present invention is directed toward beltless conveyors and, more specifically, to an indexing beltless magnetic conveyor.
2. Description of the Related Art
Conveyors are well known material handling devices which have application in a wide variety of environments for transporting objects from one place to another. For example, one type of conveyor employs a belt formed into an endless loop which is entrained about at least a pair of rollers spaced apart from one another and usually located at the opposed marginal ends of the conveyor. The rollers have sprockets at either end thereof. The spaced rollers are interconnected by a pair of chains entrained about the sprockets at either end of the rollers. An electric or hydraulic motor is usually employed to power the sprockets and continuously moves the belt over a substantial length of the conveyor between the rollers. In this way, objects may be transported by the conveyor over its length.
Conveyors find application in manufacturing environments. For example, in metal stamping operations, conveyors are employed to move parts between successive presses or from a press into a bin. In addition, conveyors are used for inspecting, transporting and assembly situations and can assist in maximizing production by removing parts, slugs or other scrap and materials from under low clearance areas like punch press dies and permitting continuous operation of the press. However, belted conveyors suffer from the disadvantage that the belts are often cut by the sharp edges of the metal parts formed in stamping operations. The useful life of the belts are reduced and the belts must be replaced more frequently. Frequent belt replacement increases the maintenance costs of the stamping operation. Further, stamped parts and other debris may pass through the damaged belts and jam or foul the inner workings of the conveyor drive system.
In part to avoid these problems, beltless conveyors are often employed in certain manufacturing operations. Metal parts are supported on a stainless steel or other non-magnetic slide surface. A plurality of strong magnets are movably supported at spaced increments beneath the non-magnetic slide surface along the length of the conveyor. The magnets cause the metal parts to be moved along the slide surface of the conveyor. Beltless magnetic conveyors obviously do not suffer from cuts or worn belts and thus have been adopted in numerous manufacturing environments. Water-tight beltless magnetic conveyors have even been submerged in coolant used in drilling, boring or other metal cutting operations. The magnetic conveyors clean the used coolant of metal or ferromagnetic contaminants so that the coolant may be recycled.
While magnetic conveyors have overcome significant problems associated with the belted conveyors of the related art, disadvantages still exist. The drive system employed to move the magnets within the conveyor is relatively complex and expensive. Like their belted counterparts, the magnetic conveyors employ sprockets supported spaced apart from one another in a housing. The sprockets are interconnected by chains or some other mechanism. Movement of the chain causes the magnet to be translated along the length of the conveyor. Parts are discharged from the conveyor as the magnets are moved about the axis of the sprocket and away from the slide surface. The magnets are then facing away from the slide surface which reduces or eliminates the magnetic attraction of the parts to the slide surface. The magnets are then cycled back toward the start of the conveyor. A hydraulic or electric motor is mounted to a motor mount located adjacent to the housing and powers at least one of the sprockets. Further, such conveyors of this type usually employ an internal take up or adjustment mechanism to ensure proper chain tension between the sprockets. An oil bath is usually located in the housing to keep all moving parts adequately lubricated.
The complexity and expense of such drive systems has become a major factor in limiting the use of magnetic conveyors in industry today. Further, as the drive systems have become more complex, the risk that any given component may break, jam or fail has also increased. Magnetic conveyors presently employed in the related art are heavy pieces of machinery which are not portable. In fact, after two to three years, magnetic conveyors are often discarded rather than reused in a different manufacturing line.
The size and particularly the thickness of magnetic conveyors have also limited their use in some circumstances. More specifically, the diameter of the sprocket required to move the magnet within the conveyor housing, the number and size of the magnets used in any given conveyor and the clearance for the magnets as they are cycled from the end of the conveyor back to the start while spaced underneath and away from the slide surface all contribute to the need for a relatively thick housing when compared with the belted conveyors.
Thus, there remains a need in the art for a conveyor that is not as susceptible to damage from sharp edges of stamped metal parts and, which at the same time, does not require a relatively complex, self-lubricating drive system. Further, there remains a need in the art for such a conveyor which presents a thin profile, is lightweight and which is also cost-effective.